598 lines
14 KiB
C
598 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* gpio-fan.c - Hwmon driver for fans connected to GPIO lines.
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*
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* Copyright (C) 2010 LaCie
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*
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* Author: Simon Guinot <sguinot@lacie.com>
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/platform_device.h>
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#include <linux/err.h>
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#include <linux/mutex.h>
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#include <linux/hwmon.h>
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#include <linux/gpio/consumer.h>
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#include <linux/of.h>
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#include <linux/of_platform.h>
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#include <linux/thermal.h>
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struct gpio_fan_speed {
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int rpm;
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int ctrl_val;
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};
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struct gpio_fan_data {
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struct device *dev;
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struct device *hwmon_dev;
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/* Cooling device if any */
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struct thermal_cooling_device *cdev;
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struct mutex lock; /* lock GPIOs operations. */
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int num_gpios;
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struct gpio_desc **gpios;
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int num_speed;
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struct gpio_fan_speed *speed;
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int speed_index;
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int resume_speed;
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bool pwm_enable;
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struct gpio_desc *alarm_gpio;
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struct work_struct alarm_work;
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};
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/*
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* Alarm GPIO.
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*/
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static void fan_alarm_notify(struct work_struct *ws)
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{
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struct gpio_fan_data *fan_data =
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container_of(ws, struct gpio_fan_data, alarm_work);
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sysfs_notify(&fan_data->hwmon_dev->kobj, NULL, "fan1_alarm");
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kobject_uevent(&fan_data->hwmon_dev->kobj, KOBJ_CHANGE);
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}
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static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id)
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{
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struct gpio_fan_data *fan_data = dev_id;
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schedule_work(&fan_data->alarm_work);
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return IRQ_NONE;
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}
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static ssize_t fan1_alarm_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
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return sprintf(buf, "%d\n",
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gpiod_get_value_cansleep(fan_data->alarm_gpio));
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}
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static DEVICE_ATTR_RO(fan1_alarm);
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static int fan_alarm_init(struct gpio_fan_data *fan_data)
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{
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int alarm_irq;
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struct device *dev = fan_data->dev;
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/*
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* If the alarm GPIO don't support interrupts, just leave
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* without initializing the fail notification support.
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*/
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alarm_irq = gpiod_to_irq(fan_data->alarm_gpio);
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if (alarm_irq <= 0)
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return 0;
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INIT_WORK(&fan_data->alarm_work, fan_alarm_notify);
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irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH);
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return devm_request_irq(dev, alarm_irq, fan_alarm_irq_handler,
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IRQF_SHARED, "GPIO fan alarm", fan_data);
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}
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/*
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* Control GPIOs.
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*/
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/* Must be called with fan_data->lock held, except during initialization. */
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static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
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{
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int i;
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for (i = 0; i < fan_data->num_gpios; i++)
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gpiod_set_value_cansleep(fan_data->gpios[i],
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(ctrl_val >> i) & 1);
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}
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static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
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{
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int i;
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int ctrl_val = 0;
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for (i = 0; i < fan_data->num_gpios; i++) {
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int value;
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value = gpiod_get_value_cansleep(fan_data->gpios[i]);
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ctrl_val |= (value << i);
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}
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return ctrl_val;
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}
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/* Must be called with fan_data->lock held, except during initialization. */
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static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
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{
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if (fan_data->speed_index == speed_index)
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return;
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__set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
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fan_data->speed_index = speed_index;
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}
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static int get_fan_speed_index(struct gpio_fan_data *fan_data)
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{
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int ctrl_val = __get_fan_ctrl(fan_data);
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int i;
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for (i = 0; i < fan_data->num_speed; i++)
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if (fan_data->speed[i].ctrl_val == ctrl_val)
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return i;
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dev_warn(fan_data->dev,
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"missing speed array entry for GPIO value 0x%x\n", ctrl_val);
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return -ENODEV;
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}
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static int rpm_to_speed_index(struct gpio_fan_data *fan_data, unsigned long rpm)
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{
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struct gpio_fan_speed *speed = fan_data->speed;
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int i;
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for (i = 0; i < fan_data->num_speed; i++)
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if (speed[i].rpm >= rpm)
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return i;
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return fan_data->num_speed - 1;
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}
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static ssize_t pwm1_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
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u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);
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return sprintf(buf, "%d\n", pwm);
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}
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static ssize_t pwm1_store(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t count)
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{
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
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unsigned long pwm;
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int speed_index;
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int ret = count;
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if (kstrtoul(buf, 10, &pwm) || pwm > 255)
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return -EINVAL;
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mutex_lock(&fan_data->lock);
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if (!fan_data->pwm_enable) {
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ret = -EPERM;
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goto exit_unlock;
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}
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speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
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set_fan_speed(fan_data, speed_index);
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exit_unlock:
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mutex_unlock(&fan_data->lock);
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return ret;
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}
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static ssize_t pwm1_enable_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
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return sprintf(buf, "%d\n", fan_data->pwm_enable);
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}
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static ssize_t pwm1_enable_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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{
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
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unsigned long val;
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if (kstrtoul(buf, 10, &val) || val > 1)
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return -EINVAL;
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if (fan_data->pwm_enable == val)
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return count;
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mutex_lock(&fan_data->lock);
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fan_data->pwm_enable = val;
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/* Disable manual control mode: set fan at full speed. */
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if (val == 0)
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set_fan_speed(fan_data, fan_data->num_speed - 1);
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mutex_unlock(&fan_data->lock);
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return count;
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}
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static ssize_t pwm1_mode_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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return sprintf(buf, "0\n");
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}
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static ssize_t fan1_min_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
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return sprintf(buf, "%d\n", fan_data->speed[0].rpm);
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}
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static ssize_t fan1_max_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
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return sprintf(buf, "%d\n",
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fan_data->speed[fan_data->num_speed - 1].rpm);
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}
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static ssize_t fan1_input_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
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return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm);
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}
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static ssize_t set_rpm(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t count)
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{
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
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unsigned long rpm;
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int ret = count;
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if (kstrtoul(buf, 10, &rpm))
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return -EINVAL;
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mutex_lock(&fan_data->lock);
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if (!fan_data->pwm_enable) {
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ret = -EPERM;
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goto exit_unlock;
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}
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set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));
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exit_unlock:
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mutex_unlock(&fan_data->lock);
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return ret;
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}
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static DEVICE_ATTR_RW(pwm1);
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static DEVICE_ATTR_RW(pwm1_enable);
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static DEVICE_ATTR_RO(pwm1_mode);
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static DEVICE_ATTR_RO(fan1_min);
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static DEVICE_ATTR_RO(fan1_max);
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static DEVICE_ATTR_RO(fan1_input);
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static DEVICE_ATTR(fan1_target, 0644, fan1_input_show, set_rpm);
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static umode_t gpio_fan_is_visible(struct kobject *kobj,
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struct attribute *attr, int index)
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{
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struct device *dev = kobj_to_dev(kobj);
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struct gpio_fan_data *data = dev_get_drvdata(dev);
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if (index == 0 && !data->alarm_gpio)
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return 0;
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if (index > 0 && !data->gpios)
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return 0;
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return attr->mode;
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}
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static struct attribute *gpio_fan_attributes[] = {
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&dev_attr_fan1_alarm.attr, /* 0 */
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&dev_attr_pwm1.attr, /* 1 */
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&dev_attr_pwm1_enable.attr,
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&dev_attr_pwm1_mode.attr,
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&dev_attr_fan1_input.attr,
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&dev_attr_fan1_target.attr,
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&dev_attr_fan1_min.attr,
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&dev_attr_fan1_max.attr,
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NULL
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};
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static const struct attribute_group gpio_fan_group = {
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.attrs = gpio_fan_attributes,
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.is_visible = gpio_fan_is_visible,
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};
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static const struct attribute_group *gpio_fan_groups[] = {
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&gpio_fan_group,
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NULL
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};
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static int fan_ctrl_init(struct gpio_fan_data *fan_data)
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{
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int num_gpios = fan_data->num_gpios;
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struct gpio_desc **gpios = fan_data->gpios;
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int i, err;
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for (i = 0; i < num_gpios; i++) {
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/*
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* The GPIO descriptors were retrieved with GPIOD_ASIS so here
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* we set the GPIO into output mode, carefully preserving the
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* current value by setting it to whatever it is already set
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* (no surprise changes in default fan speed).
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*/
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err = gpiod_direction_output(gpios[i],
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gpiod_get_value_cansleep(gpios[i]));
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if (err)
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return err;
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}
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fan_data->pwm_enable = true; /* Enable manual fan speed control. */
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fan_data->speed_index = get_fan_speed_index(fan_data);
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if (fan_data->speed_index < 0)
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return fan_data->speed_index;
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return 0;
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}
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static int gpio_fan_get_max_state(struct thermal_cooling_device *cdev,
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unsigned long *state)
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{
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struct gpio_fan_data *fan_data = cdev->devdata;
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if (!fan_data)
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return -EINVAL;
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*state = fan_data->num_speed - 1;
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return 0;
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}
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static int gpio_fan_get_cur_state(struct thermal_cooling_device *cdev,
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unsigned long *state)
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{
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struct gpio_fan_data *fan_data = cdev->devdata;
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if (!fan_data)
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return -EINVAL;
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*state = fan_data->speed_index;
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return 0;
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}
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static int gpio_fan_set_cur_state(struct thermal_cooling_device *cdev,
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unsigned long state)
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{
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struct gpio_fan_data *fan_data = cdev->devdata;
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if (!fan_data)
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return -EINVAL;
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if (state >= fan_data->num_speed)
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return -EINVAL;
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set_fan_speed(fan_data, state);
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return 0;
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}
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static const struct thermal_cooling_device_ops gpio_fan_cool_ops = {
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.get_max_state = gpio_fan_get_max_state,
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.get_cur_state = gpio_fan_get_cur_state,
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.set_cur_state = gpio_fan_set_cur_state,
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};
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/*
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* Translate OpenFirmware node properties into platform_data
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*/
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static int gpio_fan_get_of_data(struct gpio_fan_data *fan_data)
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{
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struct gpio_fan_speed *speed;
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struct device *dev = fan_data->dev;
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struct device_node *np = dev->of_node;
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struct gpio_desc **gpios;
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unsigned i;
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u32 u;
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struct property *prop;
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const __be32 *p;
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/* Alarm GPIO if one exists */
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fan_data->alarm_gpio = devm_gpiod_get_optional(dev, "alarm", GPIOD_IN);
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if (IS_ERR(fan_data->alarm_gpio))
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return PTR_ERR(fan_data->alarm_gpio);
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/* Fill GPIO pin array */
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fan_data->num_gpios = gpiod_count(dev, NULL);
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if (fan_data->num_gpios <= 0) {
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if (fan_data->alarm_gpio)
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return 0;
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dev_err(dev, "DT properties empty / missing");
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return -ENODEV;
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}
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gpios = devm_kcalloc(dev,
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fan_data->num_gpios, sizeof(struct gpio_desc *),
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GFP_KERNEL);
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if (!gpios)
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return -ENOMEM;
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for (i = 0; i < fan_data->num_gpios; i++) {
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gpios[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
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if (IS_ERR(gpios[i]))
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return PTR_ERR(gpios[i]);
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}
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fan_data->gpios = gpios;
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/* Get number of RPM/ctrl_val pairs in speed map */
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prop = of_find_property(np, "gpio-fan,speed-map", &i);
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if (!prop) {
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dev_err(dev, "gpio-fan,speed-map DT property missing");
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return -ENODEV;
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}
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i = i / sizeof(u32);
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if (i == 0 || i & 1) {
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dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries");
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return -ENODEV;
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}
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fan_data->num_speed = i / 2;
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/*
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* Populate speed map
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* Speed map is in the form <RPM ctrl_val RPM ctrl_val ...>
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* this needs splitting into pairs to create gpio_fan_speed structs
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*/
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speed = devm_kcalloc(dev,
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fan_data->num_speed, sizeof(struct gpio_fan_speed),
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GFP_KERNEL);
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if (!speed)
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return -ENOMEM;
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p = NULL;
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for (i = 0; i < fan_data->num_speed; i++) {
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p = of_prop_next_u32(prop, p, &u);
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if (!p)
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return -ENODEV;
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speed[i].rpm = u;
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p = of_prop_next_u32(prop, p, &u);
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if (!p)
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return -ENODEV;
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speed[i].ctrl_val = u;
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}
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fan_data->speed = speed;
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return 0;
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}
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static const struct of_device_id of_gpio_fan_match[] = {
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{ .compatible = "gpio-fan", },
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{},
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};
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MODULE_DEVICE_TABLE(of, of_gpio_fan_match);
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static void gpio_fan_stop(void *data)
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{
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set_fan_speed(data, 0);
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}
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static int gpio_fan_probe(struct platform_device *pdev)
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{
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int err;
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struct gpio_fan_data *fan_data;
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struct device *dev = &pdev->dev;
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struct device_node *np = dev->of_node;
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fan_data = devm_kzalloc(dev, sizeof(struct gpio_fan_data),
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GFP_KERNEL);
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if (!fan_data)
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return -ENOMEM;
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fan_data->dev = dev;
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err = gpio_fan_get_of_data(fan_data);
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if (err)
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return err;
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platform_set_drvdata(pdev, fan_data);
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mutex_init(&fan_data->lock);
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/* Configure control GPIOs if available. */
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if (fan_data->gpios && fan_data->num_gpios > 0) {
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if (!fan_data->speed || fan_data->num_speed <= 1)
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return -EINVAL;
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err = fan_ctrl_init(fan_data);
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if (err)
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return err;
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err = devm_add_action_or_reset(dev, gpio_fan_stop, fan_data);
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if (err)
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return err;
|
|
}
|
|
|
|
/* Make this driver part of hwmon class. */
|
|
fan_data->hwmon_dev =
|
|
devm_hwmon_device_register_with_groups(dev,
|
|
"gpio_fan", fan_data,
|
|
gpio_fan_groups);
|
|
if (IS_ERR(fan_data->hwmon_dev))
|
|
return PTR_ERR(fan_data->hwmon_dev);
|
|
|
|
/* Configure alarm GPIO if available. */
|
|
if (fan_data->alarm_gpio) {
|
|
err = fan_alarm_init(fan_data);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
/* Optional cooling device register for Device tree platforms */
|
|
fan_data->cdev = devm_thermal_of_cooling_device_register(dev, np,
|
|
"gpio-fan", fan_data, &gpio_fan_cool_ops);
|
|
|
|
dev_info(dev, "GPIO fan initialized\n");
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void gpio_fan_shutdown(struct platform_device *pdev)
|
|
{
|
|
struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
|
|
|
|
if (fan_data->gpios)
|
|
set_fan_speed(fan_data, 0);
|
|
}
|
|
|
|
static int gpio_fan_suspend(struct device *dev)
|
|
{
|
|
struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
|
|
|
|
if (fan_data->gpios) {
|
|
fan_data->resume_speed = fan_data->speed_index;
|
|
set_fan_speed(fan_data, 0);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int gpio_fan_resume(struct device *dev)
|
|
{
|
|
struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
|
|
|
|
if (fan_data->gpios)
|
|
set_fan_speed(fan_data, fan_data->resume_speed);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static DEFINE_SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
|
|
|
|
static struct platform_driver gpio_fan_driver = {
|
|
.probe = gpio_fan_probe,
|
|
.shutdown = gpio_fan_shutdown,
|
|
.driver = {
|
|
.name = "gpio-fan",
|
|
.pm = pm_sleep_ptr(&gpio_fan_pm),
|
|
.of_match_table = of_match_ptr(of_gpio_fan_match),
|
|
},
|
|
};
|
|
|
|
module_platform_driver(gpio_fan_driver);
|
|
|
|
MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
|
|
MODULE_DESCRIPTION("GPIO FAN driver");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("platform:gpio-fan");
|